1. Field of the Invention
Generally the invention relates to mechanically harvesting fruit from trees. More specifically, the invention relates to mechanical generation of motion to move picking arms about the trees to engage the fruit and separate the fruit from the tree.
2. Description of the Prior Art
Advances in mechanical devices in the agricultural field have resulted in significant increases in the ratios of yield verses cost over the past hundred years. Citrus is one crop that has benefited from the inventive process with machines now in use to assist people in the planting and tending phases of citrus production. Machines now clear, level and layout the rows on the land. Automation in the field of irrigation allow control of watering for maximum benefit with a minimum of runoff or evaporation. Machines now apply fertilizer and other chemicals to the groves. Other machines hedge and top the trees allowing more trees per acre than ever before. Following the harvesting of the crop, machines sort, clean, package or otherwise process the fruit. Every step in the production of citrus fruit, or products made from citrus fruit, have been successfully mechanized except harvesting.
Many attempts have been made to provide mechanical means to harvest fruit. Few of these machines are in current commercial use. A machine to harvest fruit must have several qualifying characteristics while eliminating several disqualifying characteristics.
First, the machine must be capable of moving about the grove. Therefore, the machine must be narrow to fit between the rows of trees. The machine must be capable of moving from one row to another. The current layout of citrus groves place the maximum number of trees on the minimum amount of land. Therefore, the vacant land at the end of rows may be small and occasionally bordered by a drainage ditch. It is a requirement that the machine have a sharp turning radius to navigate from one row to another.
Secondly, the machine must be capable of harvesting the fruit from all elevational heights of the tree from the lowest hanging fruit the highest fruit on the tree. Preferable, the machine will only make one pass between each row of trees or, at most, two passes with each pass covering the row of trees on one side. Therefore, the picking action must provide for complete coverage of the tree.
Thirdly, the machine must be capable of harvesting most of the fruit from each tree. The harvesting of the outer and lower fruit is of little commercial value if a great deal of less accessible fruit remains. A higher rate of compensation must be paid to human pickers to pick this remaining fruit due to the increase in difficulty.
There are two major disadvantages associated with mechanical harvesting. The first is damage to the tree. The second is damage to the fruit itself. It is extremely important to avoid both of these results. Damage to the tree can result from breakage or removal of branches or unacceptable removal of leaves. Damage to the fruit includes breakage of the peel where the stem attaches or bruising from unacceptable pressure contact. Another disadvantage to avoid is damage to the grove itself. Examples of this would be excessive movement of earth by the wheels of the machine or damage to the irrigation system.
Various attempts have been made to provide a mechanical harvesting machine meeting the above requirements. These attempts have been less efficient than desired. As such, it may be appreciated that there continues to be a need for a harvesting machine having repetitive picking motion generation, resistance yielding means and release means. The repetitive picking motion generation to provide for production of a series of insertion, contact and withdraw motions to engage and pick the fruit. The resistance yielding means to provide for a prevention of the picking arm from applying pressure to the tree above a certain threshold during the insertion phase. The release means to provide for release of objects when a predetermined pressure threshold is met. The present invention substantially fulfills these needs.